Method and apparatus for decorating surfaces



Nov. 17, 1936. K. EICHSTADT METHOD AND APPARATUS FOR DECORATING SURFACES Filed Nov. 16, 1953 Patented Nov. 17, 1936 UNITED STATES PATENT OFFICE METHOD AND APPARATUS FOR DECORATING SURFACES Application November 16, 1933, Serial No. 698,329 In Germany November 28, 1932 3 Claims.

This invention relates to an improved method and apparatus for offset printing, and is especially adapted for the printing of imitation wood grains, and the like.

Machines for effecting wood grain finishes and the simulation of other natural surfaces on hard surfaces usually embody some form of a master plate or roll having a variegated indented surface, to which pigment is applied in a suitable manner, and thereafter the surplus pigment on the roll surface is scraped or removed therefrom, and a rubber or gum offset. roll is brought into contact with the pattern or pigment carrying roll to effect a transfer of the pigment from the interstices to the surface to be grained.

Indented or master or. pattern rolls or plates have been made in various ways and it is the present practice to reproduce on the plate or roll surface an etched pattern of the grain or design by the well-known photogravure process. To obtain continuous productive results at comparatively high press speeds when using such an etching roll, the transfer of the pigment from the pattern roll to the offset roll and the action of such pigment while on the offset roll between the point of application thereto and the point of application to the surface to be grained, become highly important. I

It has been found, from past experience with offset printing mechanisms, that when the pattern or master roll came in contact with the offset roll, the colors which were transferred to the offset roll from the pattern roll were torn apart. It has also been found that due to the rate of speed at which the presses were operated, and other. operating conditions, the colors did not level out on the offset roll before they were, applied to the work surface to be decorated. This disadvantage has been apparent in all offset printing presses, even where the presses were used to print the reproductions .of type, illustrations and the like on paper. However, when there is a demand for absolute sharpness of outlines and for tone values true to the natural object being simulated, such as is demanded for the successful simulating of wood grains, marbles and tiles, the disadvantage above set out becomes more pronounced. Likewise, this disadvantage is more objectionable when surfaces, other than paper, are

- being printed, such as, for instance, wood, metal,

stone or glass.

The general object of this invention is the provision of a method and apparatus, the use of which will cause the pigment or color to level and smooth out on the transfer roll, despite the comparatively high speed of operation on the press.

A more specific object is to provide a method and apparatus for treating the pigment or colors while they are on the transfer or offset roll, so as to result in a clearer and sharper reproduction which will more truly simulate the object being reproduced and at the same time prevent excessive drying of the color remaining on the offset roll after the impression has been made.

Other objects of my improved method and apparatus will become more apparent from the following description, reference being had to the accompanying drawing, and the essential features of the invention will be set forth in the claims.

In the drawing, Fig. 1 is a vertical section through an offset printing and/or graining machine, constructed to carry out my improved method; Fig. 2 is a vertical section, as indicated by the line 2-2 on Fig. 1.

In the drawing, I have indicated more or less diagrammatically an offset printing press, which includes a pattern -roll Ill. The pattern roll is provided with a grained metallic covering l I, the pattern of which may be effected in any suitable manner but preferably by the well-known photogravure process, wherein a screen is used when the carbon resist is made, preparatory to the actual etching of the roll, thus forming a screen intaglio printing process. An offset roll I5 is provided, and mounted in frictional rolling contact with the graining roll 10. At least one of the rolls is driven, as, for instance, by a suitable motor, not shown, but which is drivingly connected to one of the rolls II] or I I.

The offset or transfer roll I5 is provided with a blanket or covering 11, which may comprise rubber composition, gum, or a glycerine and glue compound, such offset rolls being well known at the present time.

Below the offset roll 15 is a work-supporting roll 20, which, as shown in Fig. 1, maintains the upper surface of the work W in contact with the periphery of the offset or transfer roll l5, so that the pigments or colors will be transferred from the roll l5 to the upper surface of the work.

The pigments or colors are applied to the pat: tern roll by a fountain ,roll 25, which contacts with the pattern roll, as shown in Fig. 1, and which rotates with its lower region in a pigmentcarrying fountain trough 26. Pigment or color trough 25 is a reciprocating doctor blade 30. This doctor blade bears against the surface of the grained or etched pattern roll I and removes all surplus pigment deposited thereon by the fountain roll 25.

A suitable scraper I8 is provided to eliminate from the offset roll any pigment remaining thereon after the transfer to the work W has been effected. A tray I9 is provided to receive such pigment or color material as it is removed from the transfer roll i by the scraper blade iii.

The mechanism above described is representative of present-day offset printing presses and graining machines, and my improved method and apparatus is readily adapted to be incorporated in such mechanism.

My improved method comprises heating the exposed surface of colors and pigments, while on the offset roll prior to the transfer of such color to the work and at the same time applying substantially no heat to the color remaining on the roll after such transfer has been made, and by so doing transform such colors or'pigments to a more liquid state, thereby permitting the colors to promptly level and smooth out on the transfer roll, and at the same time eliminating the drying out of the minute film of ink remainin on the transfer roll after the impression has been made, enabling the removal of this color in the usual manner, and allowing the printing or graining operation to be carried out at a comparatively high rate of speed.

In the past, colors on the rolls of printing couples have been heated by heating the surface of the rolls, generally by the application of heat internally to the rolls. Such heating of the rolls causes the entire surface of the rolls to become heated, resulting in the drying on the roll of the thin film of pigment remaining thereon after the impression has been made. The drying of this thin film of pigment prevents its removal from the roll and more than counter-balances the benefits derived from the heating of the rolls, by building upon the offset roll of an increasing thickness or film of dried color and detracting from the sharpness of design obtainable.

My improved method and apparatus is also especially advantageous when used in connection with presses having offset rolls made of a composition which is afiected by heat. Rolls of this type are used to a great extent to obtain the accurate results demanded in the simulating of wood grains and the like, as such rolls receive for all practical purposes all the color from the pattern roll and transfer it to the work being decorated. It has been found disadvantageous to heat such rolls internally, as such application of heat softens the rolls and to a certain extent destroys their accuracy.

In the drawing I illustrate an apparatus forheating the external surface of the roll l5. While, as above set out, this method of heating the roll i5 is especially advantageous when certain types of composition offset rolls are used, it is, nevertheless adaptable to all types of rolls and presents an advantageous method of heating the colors in existing presses wherein the construction of the offset rolls, or of the machines themselves either prevent or make the internal heating of the offset rolls diflicult.

As shown in Fig. 1, I accomplish the warming of the colors on the offset roll l5 by directing a blast of'warmed air toward the surface of the color on the roll between the point of application of the ink to the roll and the point of transfer of the ink to the work. Warmed air is drawn through a suitable conduit 60 by a fan GI and forced through a conduit 62 into a nozzle 63 having an elongated discharge opening 64 which directs the warmed air toward color on the surface of the roll I5, thereby warming the colors. The amount of heat applied to the colors on the roll is adjusted by regulating the temperature of the heated air and by adjusting the speed of the motor 65, which propels the fan 6|, thereby regulating the volume of heated air applied to the surface of the roll.

I find it desirable to prevent the heat from affecting the colors while they are in the ink fountain or on the pattern roll, as this would change the consistency of the ink itself, which consistency is maintained at a predetermined point commensurate with the nature of color being used and the speed of the press. As shown in Fig. 1, I provide a guard 10 to shield the pattern roll and ink fountain from the blast of heated air. Such guard is preferably made of a heat insulating material.

From the foregoing description it will be seen that the heated air is, due to the location of the nozzle 53, directed to only that portion of the roll which has received color from the pattern roll and has not given up its color to the work. The amount of color on this portion of the roll has suificient body to permit regulation of the amount of heat to prevent drying of the ink. Even this amount of heat would be sufficient to dry out the color remaining on the offset roll after the transfer to the work has been effected. However, by my arrangement the heat is restricted to the area of the roll having a comparatively heavy coating of color. Hence, any disadvantageous drying of the color is eliminated.

While I have illustrated my invention in connection with a rotary printing machine, it is apparent that it is equally well adapted for use in fiat bed printing or graining presses. My invention likewise is not confined to single color printing, but is equally as advantageous when used in connection with multicolor presses. In

'such instances each offset roll is heated.

1. An apparatus for decorating surfaces, comprising a frame, a roll mounted in the frame, a pattern on said roll, means to supply a color to said roll, means to remove excess color from said roll, an offset roll rotatably mounted in said frame and in contact with such pattern roll to receive the color therefrom, means to support articles to be decorated in contact with said transfer roll whereby color is transferred to such articles, means to heat the color after it has been transferred to said offset roll and before it has been transferred to the article to be decorated, said last-named means including means to force a current of heated air toward substantially all of the color on said offset roll 'and simultaneously toward the work to be decorated, and means to shield the pattern roll from such heated current of air.

2. The method of decorating surfaces comprising the transferring of color from a pattern to an offset printing roll, thereafter transferring such color to the work to be decorated, removing the color remaining on the roll after the transfer to the work has been efiected, and including applying heat to the color on the offset roll between the point of application thereto 7 a,ooo,ao1 3 means to remove from said roll the color rea i transferred from the oifset roll to such articles,

maining thereon after the transfer to the work has been effected, and means to heat the color on the roll between the point of application thereto and thepoint of contact with the work without applying .heat to the color on the roll while it is between the point of contact with the work and the color removing means.

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